In a communications system, a multiple access manner allows multiple mobile users to simultaneously share limited spectrum resources. Frequency Division Multiple Access (FDMA for short), Time Division Multiple Access (TDMA for short), and Code Division Multiple Access (CDMA for short) are three major access technologies for sharing effective bandwidth in a communications system. A combination of an orthogonal frequency division multiplexing technology (OFDM for short) and a multiple access technology can allow multiple users to simultaneously share limited spectrums, so as to obtain a relatively high system capacity.
At present, in an orthogonal frequency division multiplexing-Time Division Multiple Access (OFDM-TDMA) technology, a two-way service is mainly implemented in a time division duplex (TDD for short) manner, that is, communication from a remote end to a local end is performed in some timeslots, and communication from the local end to the remote end is performed in other timeslots, which causes problems of low spectrum utilization and increased overheads for uplink and downlink scheduling.